Automatic fire alarm



Sept. 1, 1931. A. H. PEARSON AUTOMATIC FIRE ALARM Filed July 6. 1929 2 Sheets-Sheet l Inventor la 15 1, 21 mm Sept. 1, 1931. A. H. PEARSON AUTOMATIC FIRE ALARM Filed July 6. 1929 2: Sheets-Sheet. 2

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l atented Sept. 1, 1931 PATENT OFFICE AXEL H. FEARS ON, OF CERESCO, NEBRASKA AUTOMATIC FIRE ALARM Application filed July 6, 1929.

This invention relates to automatic fire alarm devices and has for its primary bect the provision of certain novel and useful improvements in systems of this type, the

invention being characterized by a novel arrangement and construction of parts, which render the system simple in construction and operation, thoroughly reliable, practical, strong, durable, and Well adapted for 1 the purpose designed. The invention consists in the provision of a sound emitting de vice arranged in circuit with a plurality of switches, each of the switches being normally held open through the medium of suitable heat affecter devices, whereby upon an outbreak of fire, either thefiames from the fire or the heat radiated therefrom will destroy the means maintaining the switches in open position, thus permitting a closing of the switch or switches to permit an operation of the sounding device whereby one may be quickly warned of the situation.

Other objects and advantages of this invention, Wll become more apparent to the E reader during a study of the following description, taken in connection with the accompanying drawings, wherein:

Figure 1 is a side elevation of a device embodyin this invention, the casing for con 5 taining and protecting the source of electrical supply being broken away.

Figure 2 is a side elevation of a switch mechanism constructed in accordance with this invention, the switch being shown in an 3 5 open position.

Figure 3 is a top plan View thereof.

Figure 4 is a Vertical transverse sectional view taken substantially on line 44 of Figure 2.

Figure 5 is a diagrammatic view of the system showing the same installed in a dwelling.

Figure 6 is a view similar to Figure 4 and taken on line 6-6 of Figure 2, looking in :3 the direction of the arrows.

\Vith reference more in detail to the drawings, it will be seen that the invention contemplates the provision of a suitable, substantially rectangular casing 5, which is open at one end. A closure or cover 6 fits down Serial No. 376,444.

over the casing for closing the open end of the casing. Located adjacent the casing 5 is a suitable source of electrical energy such as herein designated, comprising a plurality of dry cell batteries 7 in suitable circuit one with another, the number of batteries being of course variable, to suit conditions. I

One end wall of the housing is provided with a suitable opening 8 and disposed opposite to the opening for substantially clos ing the same is a plate 9 of mica or suitable similar material which mica is disposed with a suitable frame 10 which is bolted or otherwise secured to the end wall of the housing.

A clear knowledge of this frame willbe best gleaned when attention is directed to one side wall of the housing 5, wherein there is provided a second opening which is also enclosed with a plate of mica 9' located within a frame 10 surrounding the opening for maintaining the mica plate 9 in closed position with respect to the opening, and it will be seen that this frame 10 is provided with diametrically opposed apertured ears for the reception of suitable bolts, screws or other fastening elements 11, whereby the same may be secured in position about the opening.

In this connection it is to be mentioned that the frame 10 is in every way similar to the frame 10'. Located adjacent this openand secured to the housing 5 on the same side wall of the housing is a suitable horn structure designated generally by the ref erence character 19.. The horn structure 12 is fixed in position to the side of the housing 5 through the medium of suitable supporting bracket 13. Located within the housing 1d of the horn a suitable electric motor is disposed for actuating the horn. The structure of the horn 12 and its motor 14 is conventional and a detailed description thereof is deemed unnecessary.

A suitable electric conduit wire 15 to be connected to a suitable switch mechanism designated generally by the reference char acter 1.6, which mechanism 16 will be herein after more fully described. A negative conduit wire 17leads from the battery on the other end and has suitable connection as at 18 to the motor within the casing 14 of the horn 12.

Attention is now directed to my switch mechanism, wherein it is to be noted that the same consists of a substantially rectangular frame 18. A fork 19 has its legs 2O located within the frame 18 and a pivot shaft or rod 21 has its opposite ends extending through the side members of the frame 18 adjacent one end of the frame. The extremities of the legs 2020' of the fork member 19 are also suitably apertured so as to receive a pivot pin 21.

Adjacent their opposite ends the legs 20-20 of the fork 19 converge inwardly towards one another to determinate in spaced parallel extensions 2222. An elongated copper plate 23 of a length substantially equal to the length of the fork 19 extends longitudinally of the fork and one end of this plate 23 is connected to an intermediate position of the pivot pin 21 while the op posite end portion of the plate 23 extends between the extensions 22-22 of the fork as clearly shown in Figure 3. Suitable clamping bolts 24 pass through the extensions 22 22 and that portion of the plate 23 clamps therebetween for holding the said extensions and plate 23 in clamped relation.

As shownto advantage of Figure 2, that portion of the plate between the extensions 2222 is extended downwardly at its lower edge as M23. The purpose of this will be hereinafter more fully disclosed. To an intermediate portion of each of the legs 20 of the fork 19 there is pivotally connected a guide bore 24, said guide bore being longitudinally slotted as at 24. A stud or pin 26 extends laterally from the outer face of each of the side members of the frame 18, and the pin is receivable in the slot of the guide pin. Thus it will be seen that this pin and slot connection will act as a stop when the fork member 19 is moved upwardly upon its pivotal connection.

A substantially U-shaped bracket plate 27 is located within the frame 18 adjacent one end of the frame and this bracket plate 27 has its legs bolted or otherwise secured as at 28 to the end member of the frame 18 as clearly suggested in Figure 3. The purpose of the bracket plate 27 will be also hereinafter more fully set forth. At this last mentioned end of the frame 18 I provide a plurality of layers 29 of mica, the layers being disposed side by side as clearly shown. The innermost layer is disposed against the outer face of the end member of the frame 18, and a contact plate 30 is disposed against the outermost of these layers 29.

As shown to advantage in Figure 6, this contact plate 30 extends upwardly beyond the top edge of the layers 29, and upon its lower edge the contact plate has a reduced extension 31 which terminates substantially even with the lower edges of the layers. Additional layers 29', also of mica, are disposed on the opposite face of the contact plate 30 and to the outermost face of the outer layer 29 I propose to place a suitable plate 32. Bolts or rivets 33 extend through the plate 32, the layers 29', the layers 29 and also through the end member of the frame 18, as shown in Figure 3. These bolts extend on opposite sides of the extension 31 of: the plate 30 so as to be out of contact with this plate, and at the same time securely clamp the plate 30 between the layers 29 and 29, the entire arrangement being neat and compact as shown.

Obviously the plate 30 constitutes the stationary contact of the switch, while the plate constitutes the movable contact of the switch, which is designated generally by the reference character 16. For norn'ially maintaining the movable contact 2 3 out of engagement with the stationary contact, 1 provide a suitable block 3% of celluloid or other similar heat affected material, said block 34 being located between the legs of the U-shaped plate 27 in spaced relation with the ground portion of the plate tl rough the medium of suitable screws which a re threadcd in spaced relation through the ground portion of the plate 22" and the lower portion of the block 34 as clearly shown in Figure 3. The block 34 extenns upwardly beyond the top edge of the stationary contact plate 30 so that the extending portion 23 of the inoy able contact 23 may rest on the top edge of this plat 34 and stationary contact 30.

The fork member 19 is consequently disposed in that position shown in Figure llv is yet to be mentioned that the free ends of the extensions 22 of the fork 19 there E1 suitably secured weights 36, there being one weight to eacn of the said extensions. Oi vi-ously the weights 36 will aid in urging the fork 19 downwardly so that the cxtcn 7 of the plate 23 may as it were cut through the celluloid when the same h: 1'

become affected by heat so as to be; its melting and in this way hastening the closing of the switch 16. 7

At one veitical edge thereof the plate 3-9 is provided with an extension 30 which is suitably apertured for the reception of a 5- t screw 37 that a suitable (.(i'nlruloi' n have one end thereof connected thereto the opposite end of the conductor. not shown, being suital'ly connected in circuit with the motor within the housing 11!; of the horn .2, as is apparent.

The frame 18 of the switch 16 has one side member thereof provided with a suitable bracket 38. and bolts 39 extend through suitable openings formed in the plate and through that side wall of the housing 5 to which the horn 12 is attached. as clearly shown in Figure 1.

As shown diagrammatically in Figure 5, in the application of my device the battery containing casing 5, the horn 12, and switch 16 secured to one side thereof is as a unit located in one room of the dwelling, herein the dwelling being designated generally by the reference character A. Located within the separate room of the dwelling or in the basement, first floor, second floor, and in the chimney of the dwelling, one Wlilllll each room are located a switch 16, all of which switches 16 constructed in every way similar to the switch 16 as herein just described.

lit conductor 41 .eacs from the motor of the horn 12to one oi the switches 16 we the positive condo :tor 15 leads tron tor on the other end oi the series teries to the negative side of the swit h 16, The rcmainin switchin circuit with the iositive H duciors l5 and ll respectively as o matically shown in Figur 5. The conm 15 leads from the i iositive wire 15 azconnected as a 42 to th/ contar plate adjacent the pivoted end portion o the plate as shovn in Figure 3. A suitable connector wire 43 will. ot course have one end lined to the stationary contact 330 three I the medinm oi tire ear 30 beir j connected thereto through the medium oi the set screw 37, said conductor 43 being a b *anch of the conductor 41, which conductor 4:1 is connected in circuit with the motor of the horn 12,

Obviously then, actuation of any oi the switches 16 to assume a closed position will of course close the circuit from the battery 7 to the motor of the horn, whereby the horn will be sounoed. Occupants ot the dwr or these nearby will be quickly u 0 fire.

The switch 16 and switches 16 are maintained in an open position or hat posit on shown in Figure 2 with regard to switch 16 Of course, when the breaks out, the temperature of the room in which either of the switches may be located becomes such as to melt the celllnoid 34, the Pl'cSSlll'G oi" the v i mm a ole weights 36 upon l he lorl: 1.9 will of (on so cause downward movement 0 the tori; on its pivotal connection to permit the movable contact 23 to engage with the stationary contact 30 to close the circuitbetween the batteries and the motor of the horn upon which the horn is then sounded for a pur pose obvious.

It is important that at least one switch, such as the switch 16, be secured to the casing 5 which contains the batteries '1', in this mai ner protecting the batteries and the horn 12 since obviously the celluloid 34 will melt to ermit a closing of the switch before damage can he done to the batteries to the horn.

If however, the switches were scattered throughout the house, and all ot the said switches remote from the casing 5 and horn 12 obviously if the tire would enter the casing where the horn is located damage would of course he done to the batteries and the horn before one of the switches could be put into operation thus oi course rendering the device es; and incapable r". performing the innel-lowevr, in assembling the source o" electrical energy, the switch mechanism and the horn all in a compact sfrucuni t as shown, eliminating such i' -cr and the device is at all times capable V r indc the conditions stated. From the :O'JQflfililfi, it will be seen H i have provided an au;o.nati alarm device itor tires which will at all times he oositire in operation, is strong, durable, simple in construetion, yet thoroughly reliable, practical and eliicient in use.

Even thou ucrihrd the l have herein shown and deerred embodnnent oi my ne is ices iully coinprehendwl bv rentii'iu, it 1o be under-sired that the so bllFi all, as described my invention, what I wish aim is:

1. A s vitch adap ed to be arranged in t mill circuit and comprisinp; a frame, an ati, i 1 -1 w L 1 a4- tacning pnuo came by me name, a lunar 1 member fixed he raire at one e d hei- )er, a contact twee i the me abers of said having one o beyond the correspond;n51 edge of said tori: members, a bra-hot on that end of the tran e adjacent the cont ct on said frame, a fusible block carried by s bracket, said block having a grooy'ed edge normally receirirthe extended edge of said second i'nentioned mtact plate, whereby upon i usin of said block said contacts are engaged one with the other for closing the circuit, and a weight men'iber on said for]: remote from the pivoted end of the fork.

2. A w sch oi the character described comprising in eoinbin, ion a pair of complemental members piroed a one end, a contact plate clamped between said members, a contact plate, snn'iorting 163118 therefor, a fusible element 0 d re tired 1o par oted end of said complemental members.

In testimony whereot l aitix my signature,

AXEL H. P lit-EON, 

